By Harry Johnstone

“The first time that I saw a glacial lake it really blew my imagination,” says Deo Raj Gurung, “one kilometre in length, half a kilometre in width, a few hundred metres in depth. That stretch, a blue mass of water, up there in the mountain… Later, I reflected on how that amount of water could affect the communities below; it would be disastrous.”

Gurung, who works for the Aga Khan Agency for Habitat (AKAH), is remembering his first field trip to a high-altitude glacial lake in Raphstreng Tsho, north Bhutan, in 1999. Since then, because of global warming, these kinds of lakes have multiplied throughout the Himalayan mountain range. Glacial lake flooding, along with other impacts of highland climate change, now threaten hundreds of millions of people across South Asia.

Around 5,000 of the Himalayan glacial lakes are at risk of flooding, according to Elisa Palazzi, researcher at the University of Torino. The phenomenon is known as a glacial lake outburst flood (GLOF): the outer wall of rock and sediment breaches and suddenly a mass of water plunges down the mountainside. For villagers up in the mountains, warm spring weather now causes anxiety because of the threat of GLOFs.

The 2021 Intergovernmental Panel on Climate Change (IPCC) report recognised that mountain glaciers are “committed to melting for decades or centuries”. Observers like Gurung believe the 2022 flooding across Pakistan was due to two phenomena that can be attributable to climate change: melting glaciers and an early monsoon.“When you have both together,” says Gurung, “most of the time, it results in flooding.”

For Pakistan, the consequences were catastrophic: over 1,700 people were killed, 33 million people impacted or displaced, with damage and economic losses amounting to nearly $30 billion.

Mountaineers offer another, valuable perspective. Their attentiveness to conditions and climate in high altitudes is crucial for taking the right decisions. Abdul Joshi became the first Pakistani mountaineer to climb Annapurna in 2021. Last spring, he ascended Everest, partly to raise awareness about climate change. He is certainly observing changing weather patterns.

“When I summited Mount Everest,” he says, “there was a huge weather window for it; many days of clear weather. Well, that worked well for the climbers but I’m not so sure about the nature and the mountains and glaciers.”

The changing climate in mountainous areas matters, because mountains matter. Palazzi describes how mountains comprise a quarter of the Earth’s land surface and are home to over 1.5 billion people; one in every five of us. They offer sites of great cultural and spiritual significance. They support a quarter of terrestrial biodiversity. They regulate the water cycle. Mountains provide all species with freshwater and food. These “gifts”, as Palazzi calls them, must be preserved for all forms of life to survive and flourish.

But mountains are “climate hotspots”: temperatures are rising higher and faster in mountainous regions than lowland areas. The devastating impacts are clear: GLOFs, avalanches, variable rainfall, landslides, water scarcity and agricultural disruption. These dangers threaten hundreds of millions of people across the entire Indo-Gangetic plain. Calamitous human migration, sweeping down from the mountains and valleys and into the settlements below, is eminently possible. As Palazzi says: “What happens in the mountains does not stay in the mountains.”

Manzour Ali, from Gilgit, in northern Pakistan, describes his childhood days hiking in the mountains with his grandfather’s goats. Back then, the animals would graze amongst the juniper and khao trees. Occasionally, upon the slopes, Ali would see wolves and wild cats as well as red-legged partridges. Today, though, the trees are gone, felled, and the animals hunted into oblivion. Unfortunately, the worrying impacts of climate change are being compounded by human activities that are damaging fragile mountain ecosystems.

With no trees, the fields and livelihoods of mountain communities are more exposed to natural hazards, like landslides. Such disasters, in turn, can weaken local food supplies, making communities even more vulnerable.

Yet the villages inhabiting higher altitudes also possess vital local knowledge. As Rosa Laura Romeo and Sara Manuelli from the Mountain Partnership Secretariat at the Food and Agriculture Organisation (FAO) of the United Nations emphasise, highland peoples, from the High Atlas to the Hindu Kush, are rich in practices like terracing, agro-forestry and artisanal production. These ways of working often preserve both livelihoods and ecosystems. They also nurture traditions and culture, like crafts, song, dance, folklore and spiritual practices, that give meaning to place and community. Losing these customs, therefore, can impoverish social life as much as biodiversity and local economies.

The response, it seems, must cover a range of actions simultaneously. On the mountain slopes, communities can reduce the risks of floods and landslides by working with local government, NGOs and international organisations to create buffers like check dams in targeted areas. Where Manzour Ali lives in Gilgit, with the support of AKAH, this is exactly what the village has been doing, using stones and earth to build up their defences.

More broadly, Elisa Palazzi says that better assessment of the risks is required, using improved climate data, more monitoring stations at different heights and locations, and advanced climate modelling technologies.

AKAH and others have gone some way to capturing this data. This is helping mountain communities and national authorities understand and plan the appropriate responses to looming risks. But much more must be done to safeguard those on the frontlines of climate-induced disasters.

This map shows the risks that a village in the Pamir Mountains of Tajikistan faces from avalanches, debris flows and other hazards.

Romeo and Manuelli from FAO argue that within mountain communities, empowering women legally, politically and socially is crucial, given the role they play as stewards and custodians of local practices.

Romeo also emphasises that decentralised governance and economic planning is key. “Mountain people want to continue living in these areas,” she says, “But unless they get the same services as people down the mountain, they will move to the lowlands. We need to invest in mountain areas, in local economies and local services in these areas.”

Arguably the most important response to climate risks for mountain communities is also the most challenging: limiting global temperature rises by cutting greenhouse gas (GHG) emissions. The Earth’s atmosphere, that thin layer of gases protecting the planet, is currently too full of anthropogenic GHGs, and the quantities are growing daily, despite all the proclamations from people below. The impacts are already being felt. These biospheric phenomena remain locked-in for decades to come. Globally, we must adapt to these impacts and simultaneously wean our societies off hydrocarbons, all within a few years. The task is unprecedented in its magnitude.

Beyond the technicalities of policy lies another point, about the cultural significance of mountains. Mount Kailash, Kōya, Tacoma and Machu Picchu are just some of the mountains perceived as sacred by civilisations around the world. The magnificence that mountains can reveal is surely relevant. I once stood near the summit of Mount Kenya at dusk and saw the clouds beneath me, illuminated; an unending blanket of glowing, pink floss. The experience shifted my consciousness. Combining this love of the natural world with our care for human life can be transformative.

I remember the fearful vision of Deo Raj Gurung: a massive glacial lake breaching and the subsequent flood destroying everything beneath it. I imagine hundreds of these, thousands, around South Asia’s mountain ranges and the damage they could do. In the region, and globally, we are at an inflection point on climate change: do we accept the 2022 Pakistan floods as a “new normal”? Or do we step up and genuinely change the course of events? Doing so will not be easy, but the alternative is unconscionable.

Harry Johnstone is a freelance journalist, whose reports on climate change and food security issues have appeared in the Financial Times and The Guardian.

Watch the film The Sky is Far, The Earth is Tough